The present invention relates to a method of manufacturing a color filter by forming and arranging a plurality of colored filter elements on a transparent substrate, the color filter, a liquid crystal display apparatus, and an apparatus having the liquid crystal display apparatus.
With recent advances in personal computers, especially portable personal computers, the demand tends to arise for liquid crystal displays, especially color liquid crystal displays. However, in order to further popularize the use of liquid crystal displays, a reduction in cost must be achieved. Especially, it is required to reduce the cost of a color filter which occupies a large proportion of the total cost. Various methods have been tried to satisfy the required characteristics of color filters while meeting the above requirements. However, any method capable of satisfying all the requirements has not been established. The respective methods will be described below. The first method is a coloring method, which is the most popular method. In the coloring method, a water-soluble polymer material as a colorable material is coated on a glass substrate, and the coating is patterned into a desired shape by a photolithography process. The obtained pattern is dipped in a color bath to obtain a colored pattern. This process is repeated three times to form R, G, and B color filter layers.
The second method is a pigment dispersion method, which is currently replacing the coloring method. In this method, a pigment-dispersed photosensitive resin layer is formed on a substrate and patterned into a single-color pattern. This process is repeated three times to obtain R, G, and B color filter layers.
The third method is an electrodeposition method. In this method, a transparent electrode is patterned on a substrate, and the resultant structure is dipped in an electrodeposition coating fluid containing a pigment, a resin, an electrolyte, and the like to be colored in the first color by electrodeposition. This process is repeated three times to form R, G, and B color filter layers. Finally, these layers are calcined.
The fourth method is a method of dispersing a pigment in a thermosetting resin, performing a print operation three times to form R, G, and B coatings separately, and thermosetting the resins, thereby forming colored layers. In either of the above methods, a protective layer is generally formed on the colored layers.
The point common to these methods is that the same process must be repeated three times to obtain layers colored in three colors, i.e., R, G, and B. This causes an increase in cost. In addition, as the number of processes increases, the yield decreases. In the electrodeposition method, limitations are imposed on pattern shapes which can be formed. For this reason, with the existing techniques, this method cannot be applied to TFTs. In the print method, a pattern with a fine pitch cannot be formed because of poor resolution and poor evenness.
In order to eliminate these drawbacks, methods of manufacturing color filters by an ink-jet system are disclosed in Japanese Patent Laid-Open Nos. 59-75205, 63-235901, 1-217320, and 4-123005.
The above manufacturing methods by the conventional ink-jet system cannot manufacture a satisfactory color filter in view of ink blurring, color mixing between adjacent filter elements, white omissions, and the like.